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Distribution of Chaos Scroll Results

General MapleStory Forum Talk about MapleStory in general

XcoldshadowX Level 22 Windia

Introduction

Having gotten my 5 year old character to level 200 I'm ready to leave Maplestory behind and move on. However, before I leave I'd like to answer a question that I've pondered over for a while: How are chaos scroll results determined? Most people assume that chaos scroll results are uniform; that there is an equal probability of obtaining each change. However, my experience using chaos scrolls leads me to believe that the results may be approximately normally distributed; the chance of getting a +1 is greater than the chance of getting a +2, +2 greater than +3, ect.

Probability Distributions

The two distributions that I will be focusing on in this experiment are the [url=http://en.wikipedia.org/wiki/Uniform_distribution_%28discrete%29]uniform distribution[/url] and the [url=http://stattrek.com/lesson2/normal.aspx]normal distribution[/url].

The uniform distribution is exactly what it sounds like; every outcome has the same probability of occurring. The rolling of a die is an example of a uniform distribution; each outcome of the die has an equal probability of occurring (1/6). If you roll the die many times, you will find that each result appeared an approximately equal number of times. The outcomes will be distributed approximately uniformly link

The normal distribution is a distribution in which the probability of an event decreases as you further deviate from an expected result. For this you can picture the rolling of two dice and taking their sum (assuming each die is independent, which is a safe assumption). There is only one way to get a sum of 2 (1 & 1) or 12 (6 & 6), but multiple ways to get a sum of 3 (1 & 2|2 &1) , a sum of 7 (1&6|2&5|3&4|4&3|5&2|6&1 ). Therefore, you'd expect to get a sum of 7 more than you'd expect to get a sum of 2 or a sum of 12. Here is the [url=http://www.caspercomsci.com/images/diceprogram_files/Image41.gif]theoretical distribution[/url] of summing dice results; each probability is determined by dividing the possible outcomes for each event by the total number out outcomes. For a sum of 2 this is 1/36; for a sum of 7 this is 6/36. If you were to roll a die many times you'd expect the results to resemble this. Notice that the distribution is symmetrical; the probability of getting an 8 is the same as the probability of getting a 6. Also notice the bell-like shape of the distribution. This is characteristic of normal distributions and is known as a Bell Curve.

Chaos Scrolls

Chaos scrolls have the ability to make each stat better or worse by a maximum of 5 points. The possible results of a chaos scroll on a stat are: +5, +4, +3, +2, +1, 0, -1, -2, -3, -4, -5 (for +hp/mp multiply each number by 10). If chaos scroll results are normally distributed then each outcome has a probability of 1/11 of happening. If the results are normally distributed then each outcome has an unknown probability. No change would be the most likely, +-1 would be the next most likely, ect.

Assumptions

-Each stat on an item is independent from other stats
-Chaos scroll results are independent from each other
-All stats change in the same way (int and mdef have the same probability distribution)
-Chaos scroll changes do not depend on the quantity of a stat on an item as long as the stat exists on the item (a+10 stat changes with the same probability distribution as a +180 stat)

Requirements

-The chaos scroll must be successful
-A stat must be 5 or greater before the chaos scroll(50 or greater for hp/mp) for the result to be recorded. If a stat is less than 5 and a chaos scroll takes the stat away, then I am left with an ambiguous result (was it -5 or -4?). To eliminate this, I will simply ignore the change to a stat that is 4 or less and consider this stat invalid for the current chaos scroll. Since I am assuming that the quantity of a stat does not affect a chaos scroll I've eliminated the issue.

Method

-I will buy many chaos scrolls, hopefully well over 100.
-I will chaos items that will give me many valid results. The items that I am currently focusing on are lvl 70 maple hats (10 valid stats), targa helms, scar helms, and zhelms (8 valid stats)
-The results will be recorded

Results


-After 81 valid changes this is the graph that was produced.
I need to wait for some of my stuff to sell before I can do more. This is a work in progress and I will try to update this thread as much as I can until the results are satisfactory.

-After 248 valid changes this is the graph that was produced.
The Bell Curve is becoming apparent; most values are clustered towards the center of the graph. It's almost obvious at this point that the probability of having a stat change by 5 is not the same as the probability of a stat changing by 1. I'd still like to keep going with this.

If you have any questions or comments, or if you see an error anywhere in my post (a careless definition, spelling error, ect), please let me know. If you'd like to contribute then please post your raw data in the comments.

*NEW* Contributing

If you'd like to contribute data, please take a screenshot of the item after each successful chaos scroll and place it on an image hosting site such asimgur as an album. Here's an example

Eratta


EDIT: Added sentences about the Bell Curve
Posted: January 2012 Permalink

Replies

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I'm glad somebody finally did this
Jan 02 2012
Like are you pro in calcuslas
Get a PHD in math
Jan 02 2012
Have you run the data through a QQ plot? that would probably be sufficient for testing normality with the number of tests youve run... especially seeing as how the normality seems pretty apparent.
Jan 02 2012
Spirit Level 156 Galicia Bow Master
Like are you pro in calcuslas
Get a PHD in math [/quote]

o__o
This doesn't requre any math skill at all. All it is is just collecting data. You learn this in Algebra II, or at least in my school we do. If you consider [i]this[/i] to be the level of Calculus...
Jan 02 2012
Spirit Level 156 Galicia Bow Master
@Spirit: sarcasm [/quote]

...how was that sarcasm
Jan 02 2012
...how was that sarcasm[/quote]
Because it was the time and money, not the skills
Im in Lala land :S
Jan 02 2012
this seems like a great challenge actually. i just have two questions: will you be taking results from other users, and, if yes, what kind of evidence do you want behind the statistics (like, how do we show you that the scroll actually worked as we claim it did).
i see this as a great way to spend the coins from the legends event, and wish to participate
Jan 02 2012
Killaz5000 Level 162 Scania Bow Master
Slightly skewed to the right..
Jan 02 2012
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